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ASPHYXIA                                                     119

lion being called into play.   The blood pressure rises and the pulse becomes

In the second stage the expiratory muscles of respiration become more
active with spasmodic movements,  which are followed by  convulsions of
nearly all the muscles of the body.    Owing to venous and capillary stagna-
tion the face and hands are deeply congested and cyanosed.    Consciousness .
becomes confused and the sphincters are relaxed.

In the third stage the respiratory centre is paralysed. The muscles
become flaccid, there is complete insensibility, the reflexes are lost, and the
pupils are widely dilated. The blood pressure falls. Prolonged sighing
inspirations occur at longer and longer intervals until they cease altogether,
and death ensues. The pulse is scarcely perceptible, but the heart may
continue to beat for some minutes after respirations have quite ceased.

The three stages last for about five minutes before death takes place.
They may be prolonged for two or three times as long. Occasionally
asphyxia may bring about death almost instantly.

Post-mortem Appearances—External.—The face is either calm and pale
in slow asphyxia, or distorted, congested and blue in cases of sudden
asphyxia. The lips and nails are livid. Cadaveric lividity is more marked.
The tongue is protruded in most cases; and frothy and bloody mucus comes
from the mouth and nostrils. Rigor mortis i£ usually slow to commence, but
may be rapid in some cases.

Internal.—The mucous membrane of the trachea and larynx is cinnabar
red due to its injection and contains froth. Tj^e lungs are dark and purple
in. colour and gorged with dark venous blood; on being cut they exude
frothy, dark fluid blood. The air-cells are distended or even ruptured due
to emphysema. The right cavity of the heart is full containing dark-coloured,
imperfectly clotted blood, and so are the pulmonary artery and the venae
cavse. Tl^£ left cavity,"the aorta and the pulmonary veins are empty. In
many cases, both, sides of the heart are found to be full, if examined soon
after destth but, after rigor mortis has set in, the heart is found contracted
and empty, or the tension in the abdomen presses on the inferior vena cava,
and drives blood up into the heart. Similarly, the lungs are found heavier
with blood collected in the dependent parts if examined sometime after death,
or the tension in the abdomen or contraction of the heart muscle will drive
more blood into the lungs, irrespective of the cause of death.

The brain is congested but not so much as in death from coma. The
abdominal organs are found congested. Numerous small petechial haemor-
rhages or ecchymoses known as Tardieu's spots, are seen under the serous
membranes of various organs due to rupture of the capillaries caused by
intra-muscular pressure. These are usually round, dark and well-defined,
varying in size from a pin's head to a small lentil. They are found under
the pleurse, pericardium, thymus, meninges of the braul and cord, conjunc-
tive, and even under the skin of the face and neck. They are sometimes
seen in deaths occurring from scurvy or purpura.

Gordon's Classification of Death.—Gordonl has suggested a classification
of medico-legal deaths which is based upon the concept that the cessation of
the vital functions depends upon tissue anoxia, which is brought about in
the following four different ways : —

I. Defective oxygenation of the blood in the lungs—anoxic anoxia,
which is produced (a) by obstruction to the passage of air into the respi-
ratory tract as in suffocation, smothering and overlaying ; (b) by obstruc-
tion to the passage of air down the respiratory tract as in drowning, choking
from impaction of a foreign body, throttling, strangulation and hanging; (c)

1.   Brit. Meet. Jour., Sep. 9, 1944, p. 337.